Grab for Profits Pushes Madeira River Past Its Limits During Historic Floods

Tue, 03/11/2014 - 10:32am

By:

Zachary Hurwitz

A woman navigates a boat through the flooded streets of Porto Velho, Brazil.

Greenpeace Brasil

Excessive increases in the maximum reservoir levels of the Santo Antônio and Jirau dams, together with historic rainfall in the Amazonian state of Rondônia, Brazil, have pushed the Madeira River past its limits, causing R$455 million in damage and displacing 2,230 people. The disaster has revealed the failure of dam builders to both accurately assess the cumulative impacts of a large dam cascade and integrate climate change into hydrological models.

River Levels Never Before Seen

The rainfall was the largest ever recorded during the 47 years in which hydrology data has been gathered in the region.

In Porto Velho, flooding destroyed homes, churches, office buildings, and property in 16 neighborhoods. The city's prefecture declared a state of emergency on February 27th, as the river reached 18.81 meters, two meters above the 16.68 meter emergency maximum. The National Grid Operating System (ONS) of Brazil ordered project consortium Santo Antônio Energia, S.A. to power off the 17 turbines of the Santo Antônio Dam, in an attempt to reduce the flooding of the surrounding area.

As the families testify in the video below, no one knows if or when river and reservoir levels will drop down to normal; nor, for that matter, what the "new normal" might be.

The historic rainfall wiped away assumptions about hydrology on the river.

Greenpeace Brasil

Climate Change Unaccounted For in Dam Studies

In the Amazon, 100-year flood and drought events have become increasingly common as a result of climate change. In 2005 and 2010, two 100-year droughts hit the Manaus region in the state of Amazonas, followed by a 100-year flood there in 2012. The frequency with which 100-year events are beginning to occur should move Brazilian dam planners to adapt to the new climate reality in energy planning. But, in the case of the Santo Antônio and Jirau dams, the probability of extreme climate-related events was never factored into hydrological models.

The massive Brazilian engineering firm Odebrecht assessed the hydrology of the Madeira River for the environmental studies of the Santo Antônio and Jirau dams in 2007 and 2008. In the studies for Santo Antônio, Odebrecht calculated a maximum potential flow of 45,600 cubic meters per second (m3/s) at the state capital of Porto Velho. However, at the end of February, the maximum flow recorded at Porto Velho reached a never-before-seen 56,000 m3/s – nearly 25% higher.

A similar discrepancy is found in the hydrological studies for the Jirau Dam, which was prepared separately from the studies for Santo Antônio. In both cases, Odebrecht utilized past available historical rainfall data to model potential precipitation in the future. However, climate change is altering hydrological cycles the world over, and that should teach dam builders a lesson: past trends no longer reliably predict future ones – a concept called non-stationarity. Odebrecht did not factor non-stationarity into the two hydrological models, in effect blinding themselves to the possibility that such extreme rainfall would ever occur.

An aerial view of the Porto Velho area shows immense flooding around the Santo Antônio Dam.

Greenpeace Brasil

Bickering Over Profits Led to Bursting Reservoirs

Though Odebrecht designed the hydrological and environmental studies for both dams, two different project consortia won the EPC contract for each dam. Odebrecht participated in the winning consortium for the Santo Antônio Dam, Santo Antônio Energía, S.A., but was outbid on the Jirau Dam by another consortium, Energía Sustentável do Brasil. As construction on each dam progressed, the two consortia bickered constantly over siting and operating reservoir levels.

When Santo Antônio began operation first, followed by Jirau, each consortium sought to increase the generating capacity of their dam by raising reservoir levels and adding additional turbines. Additional energy supply could raise profits for both consortia.

In 2013, the government permitted Santo Antônio Energia, S.A. to elevate the Santo Antônio reservoir from 70.5 meters to 71.3 meters above sea level. That same year, Energía Sustentável do Brasil requested to increase the reservoir level of the Jirau Dam. However, the government did not require the consortia to undergo new environmental studies to assess the effects of these larger reservoirs.

When the historic flooding occured this year, the Jirau consortium claimed that the Santo Antônio consortium had elevated its reservoir level to a whopping 75 meters, in clear violation of permits. In a retort, the Santo Antônio consortium claimed that it had never raised levels past 70.5 meters.

While the two groups of companies bickered over who had the right to higher profits from additional capacity, neither saw this historic flood coming. Impact interactions from the two dams were never studied seriously, and climate change never made it into either project's hydrological studies. As a result, because the resevoir levels were too high, and the topography of the Amazon is flat,the extra 25% of rainfall falling on Porto Velho had nowhere to go but into people's homes. Indeed, had there been no dams in the first place, the extra rainfall would have flowed downstream through the catchment unimpeded.

A family decries the dam consortia outside their flooded home in Porto Velho.

Greenpeace Brasil

Federal Ruling Demands New Environmental Studies

The tragedy has led to judicial action that threatens the future of each dam. Federal judge Herculano Martins Nacif ruled that the two project consortia must redo the projects' environmental studies, under the supervision of environmental agency IBAMA, the National Water Agency, other federal entities, and external experts.

The studies should lead to new environmental impact assessments for both projects, incorporating knowledge about the new historic flow levels on the river. Each company has been given a 90-day deadline to prove that the studies are on course. If the studies are not, each dam's operational license could be revoked.

Yet, the extent to which either consortium can significantly take climate change into account in these new studies, and resolve their bickering over reservoir levels, remains to be seen.

For now, two projects that sought carbon money from the Clean Development Mechanism for their mitigation potential are now paradoxically helping to wreak their own kind of climate chaos on the citizens of Porto Velho.